It's difficult to pinpoint a precise moment when the office of the pope began to lose its vast political power, which had long placed the Holy See above even the kings and emperors of Europe, but has since declined to the point that now-retiring Pope Benedict XVI found few political accomplishments in his reign. But one day that stands out is Dec. 2, 1804.
A few weeks earlier, French voters had overwhelmingly approved a referendum elevating Napoleon Bonaparte from first consul to emperor, the beginning of the end of France's democratic revolution. His coronation was to proceed in the manner of all Catholic monarchs, who still ruled most of Europe: he would kneel before the pope, then Pius VII, to receive a crown and blessing. The symbolism of the coronation reflected centuries of European political tradition, in which the Catholic church formally conferred royalty with the divine blessing that was thought necessary to rule; the church, in its power, had at times competed openly with those same monarchs.
But when Napoleon marched up the altar of the Notre Dame cathedral in Paris, he did not kneel before Pope Pius VII as the French monarchs before him had done and as Pius surely expected. As Pius raised the crown, Napoleon instead turned to face the onlookers in the pews, snatched the crown out the pope's hands and placed it on his own head. In Jacques Louis David's famous painting of the incident, completed four years later, Pius stands sullenly back, watching as Napoleon crowns his wife queen.
Napoleon's coronation did not on its own end the pope's influence over world politics, but it symbolized that decline after centuries of vast papal authority over Europe. When the Roman Empire fell, the Catholic church remained as close as Europe had to a pan-continental institution; the church had legitimacy and grassroots support, not to mention vast financial resources.
European governments, as they grew from city-states to nations, developed a sort of symbiotic relationship with the church, relying on it for support and fearing its power to support opposing leaders. When Pope Urban II called on European leaders to rally for the crusades, he both confirmed and entrenched the Vatican's power over political leaders, even in matters of war. Though the pope's powers declined when European monarchs became powerful enough to challenge him, at one point hosting a second and more corruptible pope in France, the protestant reformation rallied Catholic governments against rising protestantism and renewed the pope's political importance.
But even the pope could not overcome the rise of European nationalism and revolutionary movements in the modern era, of which Napoleon was just one. The Vatican's political impotence has many examples, but one of the most powerful is Pope Pius XII's scandalous silence during the holocaust. Debate over Pius's relative inaction still rages, with critics charging that he hoped to retain some Catholic presence in Germany while defenders argue he was more quietly diplomatic.
Pope John Paul II, who reigned from 1978 to 2005, seemed to carve out a new model for a politically influential pope. Though the Polish-born leader did not wield the traditional tools of direct papal power, he acted as a sort of global ambassador on behalf the church. His remarkable tenure, in which he mediated conflicts, pressured non-democratic governments to reform and sought to soothe interfaith tensions, earned him a place in history. Cold War scholars still celebrate his role in helping to end the Cold War, which even Soviet leader Mikhail Gorbachev acknowledged.
Pope Benedict XVI, who Monday announced that he will resign at the end of the month, has a political legacy akin to many popes in the 20th century: one in which he is relevant to the theological debates within the Catholic church but not, like the popes of old, a major player in world politics. Whoever follows him will have to consider whether he wishes the papacy to remain an office principally concerned with the internal theology of the world's third-largest religion as it was under Benedict, or one that attempts to reclaim some of the global leadership of John Paul II. Either way, Benedict's resignation is a reminder of how far the papacy has come from the days of when it competed alongside kings and emperors for power.